/*
 * Created on May 14, 2007
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.util;

import org.gudy.azureus2.plugins.download.Download;
import org.gudy.azureus2.plugins.torrent.TorrentAttribute;
import org.gudy.azureus2.plugins.torrent.TorrentManager;
import org.gudy.azureus2.pluginsimpl.local.PluginInitializer;

public class DownloadUtils {
    private static TorrentAttribute ta_tracker_extensions;

    public static synchronized void initialise() {
        if (ta_tracker_extensions == null) {

            TorrentManager tm = PluginInitializer.getDefaultInterface().getTorrentManager();

            ta_tracker_extensions = tm.getAttribute(TorrentAttribute.TA_TRACKER_CLIENT_EXTENSIONS);
        }
    }

    public static synchronized void addTrackerExtension(Download download, String extension_prefix, String extension_value) {
        String extension = "&" + extension_prefix + "=" + extension_value;

        String value = download.getAttribute(ta_tracker_extensions);

        if (value != null) {

            // if already exists then bail

            if (value.indexOf(extension) != -1) {

                return;
            }

            // if prefix exists then remove existing value

            if (value.indexOf(extension_prefix) != -1) {

                String[] bits = value.split("&");

                value = "";

                for (int i = 0; i < bits.length; i++) {

                    String bit = bits[i].trim();

                    if (bit.length() == 0) {

                        continue;
                    }

                    if (!bit.startsWith(extension_prefix + "=")) {

                        value += "&" + bit;
                    }
                }
            }

            value += extension;

        } else {

            value = extension;
        }

        download.setAttribute(ta_tracker_extensions, value);
    }

    public static synchronized String getTrackerExtensions(Download download) {
        return (download.getAttribute(ta_tracker_extensions));
    }

    public static synchronized void removeTrackerExtension(Download download, String extension_prefix) {
        String value = download.getAttribute(ta_tracker_extensions);

        if (value != null) {

            int pos = value.indexOf(extension_prefix);

            if (pos == -1) {

                return;
            }

            String[] bits = value.split("&");

            value = "";

            for (int i = 0; i < bits.length; i++) {

                String bit = bits[i].trim();

                if (bit.length() == 0) {

                    continue;
                }

                if (!bit.startsWith(extension_prefix + "=")) {

                    value += "&" + bit;
                }
            }

            if (value.length() == 0) {

                value = null;
            }

            download.setAttribute(ta_tracker_extensions, value);
        }
    }
}
